A method for operating an electrohydraulic transmission clutch of a motor vehicle, wherein, for a clutch operation, a hydraulic pressure is set by way of a regulating device of a controller as a function of a clutch signal, and, through the pressure, a disengagement element of the transmission clutch is moved through a soft region into a rigid region via a rigid point, or vice versa. The soft region is to be compensated for. Further, as a function of the clutch signal, the regulating device generates a preliminary target value signal for the pressure and a time derivative of the preliminary target value signal is generated as a movement signal, and a pilot control generates a pilot control signal as a function of the movement signal, and the preliminary target value signal and the pilot control signal are combined to give a final actuating value signal for the pressure.

Abnormality detection device for automatic transmission of invention has automatic transmission 5A connected to vehicle driving source 1, 3 through clutch 4a; range detector detecting selection range of selector lever 9 and outputting detection signal; manual valve 90 configured to, when selector lever is positioned at drive range position, engage clutch and bring automatic transmission into power transmission state, and when selector lever is positioned at range position except drive range position, disengage clutch and bring automatic transmission into power non-transmission state. Device further has engagement control unit 10B controlling clutch from disengagement state toward engagement direction when no-signal state in which signal is not outputted from range detector continues for first predetermined time or more; engagement judgment unit 10C judging engagement of clutch during engagement control; and abnormality determination unit 10D determining, when engagement is judged, that range detector is in no-signal abnormality indicating that no signal is outputted.

A change-gear transmission system includes a transmission that can be switched between multiple gears, a gearshift lever for selecting between the gears of the transmission, an automatically actuatable clutch, which is arranged in a drive train in series with the transmission and a control unit for automatically opening the clutch while maintaining a gear engaged in the transmission when a condition for the transition into coasting or gliding mode is fulfilled. The control unit is configured to detect a touch of the gearshift lever by the driver, to open the clutch only when no touch of the gearshift lever is detected, and further in the case that in the coasting or gliding mode, a touch of the gearshift lever is detected, to close the clutch while maintaining the engaged gear.

Provided are a method of learning a torque-stroke relationship of a clutch, and more particularly, a clutch torque-stroke learning method in which, during a process of dividing a torque region on a torque-stroke curve (T-S curve) of a clutch into two or more regions and learning the T-S curve passing through two or more torque regions with different torque section values, by learning the curve for a first torque region (e.g., a high-torque region or a low-torque region) when the curve is learned for a second torque region with guaranteed reliability, it is possible to prevent a problem of the T-S curve not converging to a previously learned curve value when the T-S curve is continuously learned for the two or more different torque regions.

In a speed change apparatus for a vehicle, a controller stores as a clutch-disengaging shift spindle angle 1 a position at which a clutch is disengaged when a shift spindle is rotated in a first direction. The controller controls the shift spindle by a first step W1 of rotating the shift spindle in the first direction until a disengaging-side target angle Ta1 is reached; a second step W2 of returning the shift spindle in a second direction opposite to the first direction; and a third step W3 of rotating the shift spindle in the first direction up to the clutch-disengaging shift spindle angle 1 and thereafter rotating the shift spindle in the second direction to return the shift spindle, upon detection of an output from a drum angle sensor, the output corresponding to shallow engagement of dog teeth.

Abnormality detection device for automatic transmission of invention has automatic transmission 5A connected to vehicle driving source 1, 3 through clutch 4a; range detector detecting selection range of selector lever 9 and outputting detection signal; manual valve 90 configured to, when selector lever is positioned at drive range position, engage clutch and bring automatic transmission into power transmission state, and when selector lever is positioned at range position except drive range position, disengage clutch and bring automatic transmission into power non-transmission state. Device further has engagement control unit 10B controlling clutch from disengagement state toward engagement direction when no-signal state in which signal is not outputted from range detector continues for first predetermined time or more; engagement judgment unit 10C judging engagement of clutch during engagement control; and abnormality determination unit 10D determining, when engagement is judged, that range detector is in no-signal abnormality indicating that no signal is outputted.

A control apparatus that controls a four-wheel drive vehicle in which a driving force is transmitted to rear wheels via a dog clutch, a propeller shaft, and a driving force transmission apparatus is configured to, when switching to a four-wheel drive mode, reduce a difference in rotation speeds of an intermediate rotational member and a ring gear member by a frictional force between a friction surface of a friction member, which is configured such that its rotation relative to the intermediate rotational member is restricted, and a target frictional slide surface of the ring gear member, and then couple the intermediate rotational member and the ring gear member by a clutch member in a state in which engagement forces of friction clutches configured to transmit the driving force between each of first and second output rotational members and the intermediate rotational member of the driving force transmission apparatus are set to engagement forces that allow their relative rotation.

A clutch control device includes a clutch apparatus (26) configured to connect and disconnect power transmission between a prime mover (13) and an output object (21), a clutch actuator (50) configured to output a driving force for actuating the clutch apparatus (26), a controller (40) configured to control driving of the clutch actuator (50), and a clutch operator configured to operate the clutch apparatus (26) regardless of the driving of the clutch actuator (50), the controller (40) detects that there is a manual operation by the clutch operator when a difference of a predetermined value or more is detected between a reference output value of the clutch actuator (50) configured to operate the clutch apparatus (26) and a measured value of an output value of the clutch actuator (50).

A method for determining the engaged gear in a manual gearbox of a vehicle comprising a number of gears is described, wherein the vehicle comprises an engine, the manual gearbox, and at least one clutch. The method comprises the following steps: determination of the revolution rate of the engine as a function of time; differentiating the determined revolution rate of the engine against time; determination of the speed of the vehicle; and determination of the engaged gear based on characteristic curves of the revolution rate of the engine as a function of time for a number of the gears in the case of a fixed rate of engagement of the clutch, the revolution rate of the engine, the differential of the revolution rate of the engine against time and the speed of the vehicle.

Provided are a method of learning a torque-stroke relationship of a clutch, and more particularly, a clutch torque-stroke learning method in which, during a process of dividing a torque region on a torque-stroke curve (T-S curve) of a clutch into two or more regions and learning the T-S curve passing through two or more torque regions with different torque section values, by learning the curve for a first torque region (e.g., a high-torque region or a low-torque region) when the curve is learned for a second torque region with guaranteed reliability, it is possible to prevent a problem of the T-S curve not converging to a previously learned curve value when the T-S curve is continuously learned for the two or more different torque regions.